Adjustable pitch-board



(No Model.) A

G. W. OLIVER.

ADJUSTABLE PITGH BOARD. 1 No. 378,069. Patented Peb.,14,1888. v

UNITED STATES PATENT OFFICE.

n GEORGE W. OLIVER, OE OHATTANOOGA, TENNESSEE.

ADJUSTABLE PlTCH-BOARD.

SPECIFICATION forming part of Letters Patent No. 378,069, dated February 14, 1888.

Application iiled October 14, 18E5. Serial No. 179,883. (No model.)

.To aZZ whom t may colzcrm- Be it known that I, GEORGE W. OLIVER, a citizen of the United States, residing at Chattanooga, in the county of Hamilton and State of Tennessee, have invented certain new and useful Improvements in Adjustable Pitch- Boards, of which the following is a description.

This invention has relation to that class of measuring-instruments commonly known as pitch-boards, used by carpenters and joiners to lay oft1 niiters, and more particularly by stair-builders to lay off the risers and treads of stairs.

The object of the invention is to provide an instrument for the purpose mentioned which can be adjusted and set to serve as a guide for laying off work wherein steps of different treads and risers and miters of different angles are involved.

Referring to the drawings, Figure lis a plan view of a pitch-board constructed in accordance with my invention. Fig. 2 is a section of the base; Fig. 3, a section of the upright. Figs. 4 .and 5 are a side elevation and* section of the clamp; Fig. 6, a similar view of the setscrew; and Eig. 7, va crosssection on the line ff of the parts, showing the form of slot in which the clamp rides.

Like letters ot' reference indicate like parts in all the figures of the drawings.

l represents au ordinary square, which is y longitudinally slotted, as at a ci.

2 and 5 represent expansible sections of the square l,and these, like the square, are slotted, as at a3 at.

3 and 4 are extensible sections, slotted as at a5 a6, and connected to the extensions 2 and 5 by set-screws e. The sections are all connected to each other by a sliding block, d, the sides of which are concaved, as at d', Fig. 5, to it the convexed edges of the slots,as clearly shown in Fig. 7. The upper half of the sides of the block d are narrower than the lower half, so that the same can be introduced into the slots a2 a3 of adjacent sections, and so that when the screw c istightened the block is drawn upwardly and the head of the screw carried downwardly into contact with the upper side of the upper section, and in this manner the sections are lirinly bound in an adjusted position. The length of the block serves to maintain the sections in line with eachother.

ertures formed in each ofthe adjacent sections, and into awasher, e', so that when tightenedV the sections are tirmly secured together, and.vv fi i when loosened the relative position of the adjacent sections may be changed..

Now, the operation of the instrument is as follows: When it is desired to lay oft' the treads and risers of stairs, the section 5 and the adjacent portion of the square 1 are laid in aposition to indicate the tread, and the set-screws e and the screws c being loosened, the section 2 is moved upwardly on the part l, and this movement causes a movement of the sections 3 and 4 vupon each otherl until the desired height of the riser is indicated by l and 2 conjointly, when it will be found that the sections 3 and 5.form at their outer edge a straight line conforming to the edge of the plank ingwhich the steps are to be cut. The screws are now tightened, and by successively applying the instrument to the plank the treads and risers can be-readily marked and subsequently sawed out. A similar 'manipulation ot' the parts adapts the instrument to the laying out of miters of different angles.

Having described'my invention and its operation, what I claim isi The combination of the square l, havingthe beveled-edge slots a a2, and the extensions 2 5, having slots cam, with the sections 43, the former having beveled-edged slot as, and the latter slot a, the thumb-screws c, and bar d, having beveled sides d', substantially as Vshown and described.

GEORGE W. OLIVER. Witnesses:

JOHN A. LEE, Sr;7 A. DELIsLE. 

